For their latest liter-class superbikes, Aprilia and Yamaha decided to do things a little differently. Yamaha's Crossplane crankshaft breaks with tradition by positioning the YZF-R1's crankpins at 90-degree intervals, reducing crank-speed fluctuations for more fluid power delivery and improved rear-wheel traction. Aprilia shunned the inline-four arrangement from the beginning, opting to pair the RSV4R's cylinders and splay them at a narrow 65 degrees. Yamaha's improvements to the 2009 R1 earned it our Motorcycle of the Year award and the World Superbike Championship. Aprilia's clean-sheet creation was so strong that it put the Italian manufacturer on the podium nine times after a seven-year hiatus from the world stage. Clearly, being different can be a very good thing.
A cursory comparison of the latest R1 versus its predecessor is disillusioning. Vital details such as horsepower and weight have shifted-but not in the usual direction. Yamaha's flagship superbike swelled to 477 pounds wet and dropped a few ponies during its makeover, but there are tantalizing aspects of the bike that overshadow those transgressions. In addition to the familiar YCC-T ride-by-wire throttle and YCC-I variable-length intake trumpets, the retooled engine gained secondary fuel injectors. Racing technology such as the crankshaft design, the linkage associated with the fully adjustable Soqi shock and the individual damping duties of the fork legs are promising carryovers from Valentino Rossi's YZR-M1 MotoGP bike. The Deltabox twin-spar frame and swingarm were totally redesigned, revising rigidity to complement the characteristics of the "long-bang" powerplant, which churns out 146.2 rear-wheel horsepower at 11,500 rpm.
Aprilia didn't have a MotoGP machine to pattern the RSV4R after, but Honda's RC212V and Ducati's Desmosedici obviously served as proxies. The V4's steep V-angle contributes to a compact engine and leaves plenty of room for the underseat fuel tank, which helps lower the bike's center of gravity and masks the fact that it weighs 473 lbs. with all critical fluids. There's just enough room between those cylinder banks for a quartet of 48mm throttle bodies. Like the R1, the RSV4's throttle plates are operated via electric motors controlled by the ECU, and there are three selectable drive modes.
The base model RSV4R doesn't have the uprated RSV4 Factory's variable-length intake funnels, but the power curve is manipulated by shower-type upper injectors that come into play at 7000 rpm, as well as a backpressure-regulating exhaust valve that opens around the same time. The frame is polished in typical Aprilia style, with a fully adjustable Showa fork up front and a Sachs shock out back. Like weight, geometry and most of the RSV4's other pertinent figures, power output is on par with that of the R1, with 149.0 bhp at 12,250 rpm.